Today, when I start out from a complete stop, for a second or 2 I'm hearing a high pitched "harmonic" type of sound coming from the left front. If I had to guess it's that something is rubbing for a second and then letting go. Brake pad maybe? It's pretty hot here in Vegas, but today is the first time I've heard it and I can get it to happen from every 4 or 5 complete stops. Not each time. Doesn't sound dangerous, but what do you think it is?

TIA